So they were typically 300Volt DC in the 1,000 Ah range.
300KW pretty damn impressive espically for DC (Im not going to break down into DC vs AC power factors and phase angles blah blah)
This makes perfect sense as the set ups were more or less a rip off of diesel electric locomotive powertrains.
The shifting from series to parallel would change the Voltage / Current aspect.
Briefly as the voltage goes up the current goes down. DC motors are curious beasts and tend to run better at higher currents at lower voltages wherein there cousins the AC motor is just the opposite. That is as long as that current is available. Its a vicous cycle though as the overall voltage begins to fall due to lack of charge the current draw goes up inversely. You soon hit a point where the cells can no longer provide that amount of current and the voltage drops even more. This is why a boat with fully charged batteries could make lets say 12 knots at all ahead full. When the batteries are discharged and not changing the 'throttle' youll be lucky to wring out 8 knots at twice the current draw. So less speed and faster discharge. The law of diminishing returns.
BTW DC motors are more efficent than AC motors but maintance and construction costs are far greater for the DC motors while AC motors tend to be more compact which explains why typical AC units utilize AC motors.
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